Apparatus and method for forming an adhesively bonded seam between resiliently compressible fabric sheets

Abstract

An apparatus ( 21, 221, 231 ) for forming a butt seam ( 33, 233, 354 ) between opposed edges ( 32, 33, 231, 232 ) of resiliently compressible, fully cured, elastomeric, fabric sheets ( 28, 29, 228, 229, 351, 352 ), such as foamed neoprene for wet suits and dry suits. In some embodiments ( 21, 221 ) the apparatus includes fabric manipulating assembly ( 23, 223 ) which continuously compresses the sheets proximate and inwardly of the edges, preferably by a roller assembly ( 26, 27, 226, 227 ), to firmly press the opposed edges of the flexible and compressible sheets ( 28, 29, 228, 229 ) tightly together during movement and bonding along the seam ( 33, 233 ). The apparatus ( 21, 221, 331 ) preferably includes adhesive activation device in the form of an ultrasonic transducer ( 24, 222, 322 ) which contacts the neoprene pieces to activate a dry neoprene cement carried on the edges of the fabric pieces. Embodiments ( 221, 321 ) are shown which include a force applying assembly ( 224, 324 ) that hammers the foam pieces against the ultrasonic transducer horn ( 222 ), or the horn ( 322 ) against the foam pieces, to enhance sonic energy coupling and to simultaneously press the pieces together for improved adhesive bonding. A method for forming the butt seam ( 33, 233, 354 ) is described.

What is claimed is:  
     
       1. An apparatus for forming an adhesively bonded butt seam between opposed edges of at least one piece of resiliently-compressible, fully cured, foamed, elastomeric fabric having an adhesive carried on one of said edges, said edges further each having a thickness dimension parallel to said edges, said apparatus comprising: 
       a sonic energy generating device including an energy applying head positioned and dimensioned to span across said edges when placed in abutting relation and formed to apply sufficient sonic energy to said adhesive carried by one of said edges to activate said adhesive; and  
       an incremental force applying assembly including a piece-engaging member having a surface positioned and dimensioned to span across said edges and positioned on a side of said pieces opposite to and aligned with said energy applying head at a distance spaced from said energy applying head by an amount dimensioned to receive said at least one piece therebetween when said edges are positioned in abutting relationship, said force applying assembly being formed to incrementally displace at least one of said piece-engaging member and said energy applying head toward the other of said piece-engaging member and said energy applying head during the application of sonic energy to said edges to compress said at least one piece between said surface and said energy applying head in said thickness dimension at said edges by an amount sufficient to simultaneously both laterally firmly press said edges together and as a result of resilient compression in said thickness dimension to enhance sonic energy coupling with said adhesive for activation thereof adhesive bonding together of said edges.  
     
     
       2. The apparatus as defined in  claim 1  wherein, 
       said at least one piece has a thickness dimension at said edges of at least 1 millimeter;  
       said piece-engaging member is provided by a movable pressure block mounted for reciprocation between a distance about equal to said thickness dimension of said edges from said energy applying head and a distance about equal to one-half said thickness dimension of said edges from said energy applying head for compression of said at least one piece therebetween, and said force applying assembly is formed to reciprocate said pressure block.  
     
     
       3. The apparatus as defined in  claim 1  wherein, 
       said force applying assembly is formed to reciprocate said energy applying head toward and away from said piece-engaging member.  
     
     
       4. The apparatus as defined in  claim 3  wherein, 
       said force applying assembly and said energy applying head are mounted in a common manually manipulatable housing.  
     
     
       5. The apparatus as defined in  claim 2 , and 
       a transport assembly formed to advance said at least one piece past said energy applying head.  
     
     
       6. The apparatus as defined in  claim 5  wherein, 
       said force applying assembly is formed to displace said pressure block to a position of maximum displacement toward said energy applying head and hold said pressure block in said position for between about one-quarter and ore-half of a time of a complete cycle of displacement of said pressure block.  
     
     
       7. The apparatus as defined in  claim 6  wherein, 
       said transport assembly is formed to advance said at least one piece past said energy applying head with move and dwell periods of time, and said transport assembly is further coordinated with movement of said pressure block by said force applying assembly to cause said at least one piece to dwell during periods of time substantially simultaneous to the application of maximum pressure by said force applying assembly.  
     
     
       8. The apparatus as defined in  claim 7  wherein, 
       said transport assembly advances said at least one piece between said dwell periods of time by an amount not greater than a distance along said seam of a shorter of the dimension of said energy applying head and said pressure block along said seam.  
     
     
       9. The apparatus as defined in  claim 1  wherein, 
       said force applying assembly is formed for adjustment of the time during which said incremental force is applied to compress said at least one piece.  
     
     
       10. The apparatus as defined in  claim 5  wherein, 
       said transport assembly is formed to advance said at least one piece continuously past said energy applying head.  
     
     
       11. The apparatus as defined in  claim 5  wherein, 
       said transport assembly is formed to firmly urge said edges together as it advances said at least one piece.  
     
     
       12. The apparatus as defined in  claim 1  wherein, 
       said sonic energy generating device is formed to apply sonic energy to said at least one piece at a frequency of above about 10 kilohertz.  
     
     
       13. The apparatus as defined in  claim 1  wherein, 
       said force applying assembly is formed to compress said at least one piece in a thickness dimension to urge said edges laterally together by an amount producing said bonded seam.  
     
     
       14. In apparatus for activating an adhesive carried by an edge of a resiliently compressible, non-thermoplastic piece of fabric having a thickness dimension comprising: 
       a sonic energy generating device including an energy applying head having an end formed to engage one side of an area of said piece of fabric at said edge;  
       an incremental force applying member having a pressure surface mounted in aligned, opposed, spaced relation to said end of said energy applying head for engagement of an opposite side of said piece of fabric; and  
       a displacement assembly coupled and formed to rapidly incrementally displace said pressure surface to squeeze said piece of fabric in said thickness dimension against said energy applying head by at least one-half of said thickness dimension during the application of sonic energy to said piece of fabric for enhanced coupling of sonic energy with said adhesive carried by said edge for activation thereof.  
     
     
       15. The apparatus as defined in  claim 14  wherein, 
       said displacement assembly is formed for reciprocation of said pressure surface toward and away from said end of said energy applying head, and is further formed for adjustment of the minimum distance between said pressure surface and said end to enable adjustment of the pressure applied to said piece of fabric.  
     
     
       16. The apparatus as defined in  claim 15  wherein, 
       said displacement assembly is further formed for adjustment of the time at which said pressure surface is reciprocated and held at said minimum distance.  
     
     
       17. The apparatus as defined in  claim 16  wherein, 
       said pressure surface is provided on a movable pressure block, and said displacement assembly is formed for adjustment of the rate at which said pressure block is reciprocated.  
     
     
       18. The apparatus as defined in  claim 14 , and 
       a transport assembly formed to advance said piece of fabric between said end of said energy applying head and said pressure surface.  
     
     
       19. An apparatus for forming an adhesively bonded seam between opposed edges of at least one piece of resiliently-compressible, non-thermoplastic, elastomeric wetsuit and drysuit fabric comprising: 
       an adhesive activation assembly formed to apply sufficient energy to an adhesive material carried by at least one of said edge in an inactive state to activate said adhesive material for bonding together of said edges, said adhesive activation assembly being further formed to apply insufficient energy to said piece to produce plastic flow of said piece; and  
       a fabric manipulating assembly positioned on a support proximate said adhesive activation assembly and formed with at least one roller spaced from an opposed support device by a distance substantially less than a thickness dimension of each of said edges for resilient rolling compression of a portion of said piece sufficiently proximate an edge thereof to compress said edges, said roller compressing said at least one of said edges in a thickness direction parallel to said edges by a substantial amount, and said roller simultaneously applying a lateral forces to said piece proximate said portion in a direction toward said edges while said adhesive material is activated to firmly press said edges together to effect adhesive bonding of said edges.  
     
     
       20. In combination, a butt seaming apparatus and a foamed elastomeric fabric piece comprising: 
       (a) at least one resiliently-compressible, fully cured, foamed, non-thermoplastic elastomeric fabric member having two edges each having a thickness dimension and positioned at a length thereof in side-by-side abutting relation for formation of a butt seam therebetween, at least one of said edges having an adhesive carried thereon; and  
       (b) a butt seam forming apparatus including:  
       (i) a sonic energy generating device including an energy applying head dimensioned for and spanning across said edges and engaging said piece on both sides of the butt seam to be formed at a portion of said length, said sonic energy generating device being formed to apply sufficient sonic energy to said adhesive carried by one of said edges to activate said adhesive; and  
       (ii) an incremental force applying assembly having a member with a piece-engaging surface dimensioned for and spanning across said edges at said length on a side of said piece opposite to and aligned with said energy applying head, said force applying assembly being formed to incrementally displace at least one of said member and said energy applying head toward the other during application of sonic energy to said edges to apply an incremental force to said edges compressing said edges at said length in said thickness dimension by an amount sufficient to simultaneously both laterally firmly press said edges together at said length and enhance sonic energy coupling of said energy applying head with said adhesive for activation thereof and formation of a butt seam.